DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2018-0739; Product Identifier 2015-NE-07-AD]
RIN 2120-AA64

Airworthiness Directives; Pratt & Whitney Canada Corp. Turboshaft Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to supersede airworthiness directive (AD) 2015-20-
04, which applies to certain Pratt & Whitney Canada Corp. (P&WC) PT6B-
37A turboshaft engines. AD 2015-20-04 requires initial and repetitive
inspections until replacement of the No. 10 bearing, and eventual
replacement of the No. 9 bearing, both located in the engine reduction
gearbox (RGB) assembly. Since we issued AD 2015-20-04, P&WC has
determined that the repetitive inspection of the bearings has an
associated risk of gearbox damage or contamination and that the bearing
installation required by AD 2015-20-04 does not adequately address the
issue of bearing axial movement. This proposed AD would require removal
from service and replacement of the No. 9 and No. 10 position bearings.
We are proposing this AD to address the unsafe condition on these
products.

DATES: We must receive comments on this proposed AD by November 1, 2018.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:

Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the
instructions for submitting comments.

Fax: 202-493-2251.

Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.

Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact Pratt &
Whitney Canada Corp., 1000 Marie-Victorin, Longueuil, Quebec, Canada,
J4G 1A1; phone: 800-268-8000; fax: 450-647-2888; website: http://www.pwc.ca. You
may view this service information at the FAA, Engine &
Propeller Standards Branch, 1200 District Avenue, Burlington, MA 01803.
For information on the availability of this material at the FAA, call
781-238-7759.

Examining the AD Docket

You may examine the AD docket on the internet at http://www.regulations.gov
by searching for and locating Docket No. FAA-2018-0739; or in
person at the Docket Operations between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays. The AD docket contains
this NPRM, the mandatory continuing airworthiness information,
regulatory evaluation, any comments received, and other information.
The street address for Docket Operations (phone: 800-647-5527) is
listed above. Comments will be available in the AD docket shortly after
receipt.

FOR FURTHER INFORMATION CONTACT: Barbara Caufield, Aerospace Engineer,
ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; phone:
781-238-7146; fax: 781-238-7199; email: barbara.caufield@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or
arguments about this proposed AD. Send your comments to an address
listed under the ADDRESSES section. Include "Docket No. FAA-2018-0739;
Product Identifier 2015-NE-07-AD" at the beginning of your comments.
We specifically invite comments on the overall regulatory, economic,
environmental, and energy aspects of this NPRM. We will consider all
comments received by the closing date and may amend this NPRM because
of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,
including any personal information you provide. We
will also post a report summarizing each substantive verbal contact we
receive about this proposed AD.

Discussion

We issued AD 2015-20-04, Amendment 39-18282 (80 FR 61717, October
14, 2015), ("AD 2015-20-04"), for certain P&WC PT6B-37A turboshaft
engines. AD 2015-20-04 requires initial and repetitive inspections
until replacement of the No. 10 bearing, and eventual replacement of
the No. 9 bearing, both located in the engine RGB assembly. AD 2015-20-
04 resulted from reports of incorrect engine torque for PT6B-37A
engines. We issued AD 2015-20-04 to prevent axial movement at the No.
10 bearing position in the engine RGB assembly, which could result in
engine overtorque, failure of the engine, in-flight shutdown, and loss
of the helicopter.

Actions Since AD 2015-20-04 Was Issued

Since we issued AD 2015-20-04, P&WC has determined that the
repetitive inspection of the bearings in P&WC Service Bulletin (SB)
PT6B-72-39095, Revision No. 3, dated December 29, 2014, has an
associated risk of gearbox damage or contamination. P&WC also
determined that the bearing installation in P&WC SB No. PT6B-72-39092,
Revision No. 4, dated December 29, 2014, as required by AD 2015-20-04,
does not adequately address the issue of bearing axial movement.

Related Service Information Under 1 CFR Part 51

We reviewed P&WC SB No. PT6B-72-39108, dated September 30, 2016.
The SB describes procedures for replacing affected bearings. This
service information is reasonably available because the interested
parties have access to it through their normal course of business or by
the means identified in the ADDRESSES section.

Other Related Service Information

We reviewed P&WC SB No. PT6B-72-39092, Revision No. 4, dated
December 29, 2014. The service information describes procedures for
removing affected bearings.

FAA's Determination

We are proposing this AD because we evaluated all the relevant
information and determined the unsafe condition described previously is
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

This proposed AD would retain none of the requirements of AD 2015-
20-04. This proposed AD would introduce a new bearing configuration
that addresses the axial movement at the No. 9 and No. 10 bearing
positions and remove the repetitive inspection requirements of AD 2015-
20-04. This proposed AD would also remove the previously mandated
bearing configuration in P&WC SB No. PT6B-72-39092, Revision No. 4,
dated December 29, 2014.

Costs of Compliance

We estimate that this proposed AD affects 119 engines installed on
helicopters of U.S. registry.
We estimate the following costs to comply with this proposed AD:

Estimated Costs

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to
issue rules on aviation safety. Subtitle I, Section 106, describes the
authority of the FAA Administrator. Subtitle VII, Aviation Programs,
describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701, "General
requirements." Under that section, Congress charges the FAA with
promoting safe flight of civil aircraft in air commerce by prescribing
regulations for practices, methods, and procedures the Administrator
finds necessary for safety in air commerce. This regulation is within
the scope of that authority because it addresses an unsafe condition
that is likely to exist or develop on products identified in this
rulemaking action.

This AD is issued in accordance with authority delegated by the
Executive Director, Aircraft Certification Service, as authorized by
FAA Order 8000.51C. In accordance with that order, issuance of ADs is
normally a function of the Compliance and Airworthiness Division, but
during this transition period, the Executive Director has delegated the
authority to issue ADs applicable to engines, propellers, and
associated appliances to the Manager, Engine and Propeller Standards
Branch, Policy and Innovation Division.

Regulatory Findings

We have determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would not
have a substantial direct effect on the States, on the relationship
between the national Government and the States, or on the distribution
of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that the proposed regulation:

(1) Is not a "significant regulatory action" under Executive
Order 12866,

(2) Is not a "significant rule" under the DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979),

(3) Will not affect intrastate aviation in Alaska, and

(4) Will not have a significant economic impact, positive or
negative, on a substantial number of small entities under the criteria
of the Regulatory Flexibility Act.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.

The Proposed Amendment

Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by removing airworthiness directive (AD)
2015-20-04, Amendment 39-18282 (80 FR 61717, October 14, 2015), ("AD
2015-20-04"), and adding the following new AD: